Fund managers may be better equipped to weather the market storm than their passive peers because of their ability to quickly cut risk.
The haven has been favored as the coronavirus outbreak has spread beyond China, threatening a pandemic and slower growth.
A recent sale-tax hike in the country and the impact of the coronavirus have driven the yen to it's biggest two-day drop since 2017.
A flight to safety that saw funds in short-term bonds and utilities add cash as coronavirus dominated headlines has given way to a vigorous rally.
While the deadly virus threatens to harm the world economy, the funds have remained popular as the Fed signals low rates for the foreseeable future.